Kentucky bluegrass (Poa pratensis L.) is an important turf species in many areas of the world. Kentucky bluegrass is used on consumer lawns, sport fields, on golf courses and various managed turfgrass areas. The control of weeds in Kentucky bluegrass is particularly problematic. Annual grasses, such as crabgrass, foxtail, dallisgrass, and goosegrass must be controlled by use of a variety of herbicides including bensulide, dithiopyr, oxadiazon, fenoxaprop and prodiamine applied at specific rates, environmental conditions, and seasons. Results vary even when applied by experts.
N-phosphonomethylglycine, also known as glyphosate, is a well-known herbicide that has activity on a broad spectrum of plant species. Glyphosate is the active ingredient of Roundup® (Monsanto Co.), an herbicide having a desirably short half-life in the environment. When applied to a plant surface, glyphosate moves systemically through the plant. Glyphosate is phytotoxic due to its inhibition of the shikimic acid pathway, which provides a precursor for the synthesis of aromatic amino acids. Glyphosate inhibits the enzyme 5-enolpyruvyl-3-phosphoshikimate synthase (EPSPS) found in plants.
Glyphosate tolerance is a desirable phenotype in various plants. Glyphosate tolerance can be achieved by the expression of bacterial EPSPS variants and plant EPSPS variants that have lower affinity for glyphosate and therefore retain their catalytic activity in the presence of glyphosate. (See, e.g., U.S. Pat. Nos. 5,633,435; 5,094,945; 4,535,060; and 6,040,497).
Plants comprising events that confer glyphosate tolerance are known in the art. For example, U.S. Pat. No. 7,569,747, incorporated by reference herein in its entirety, relates to bentgrass event ASR-368, glyphosate tolerant plants comprising ASR-368, and methods for detecting ASR-368. There is a need, however, for other grasses tolerant to glyphosate.